The actions of man who was caught on tape pushing a referee to the ground are "hugely disappointing", a spokesman for North Harbour Rugby Union says.
North Harbour Rugby Union chief executive Brett Hollister was expected to meet police early this afternoon.
Massey Rugby Football Club was working with the union, and believed it had made good progress identifying the man who pushed the referee.
The video, which emerged last night, showed a man in shorts and a hat running towards the referee, and violently pushing him to the ground.
He is then shepherded away by other spectators and players.
The video was taken after the North Harbour colt (U-21) plate final between Marist and Massey on Saturday.
The game, held at Massey home ground Moire Park, finished with a penalty try being awarded in the final minutes. Marist won 21-20.
Speaking to Newstalk ZB this morning, North Harbour Rugby Union chief executive Brett Hollister said the video was "hugely disappointing".
"[It's] a random act really. I have spoken to the club involved and they've assured me the individual is not associated with the club, he is not a member of the Massey Club.
"Nevertheless it is incredibly disappointing."
Mr Hollister said the club was now deciding what action to take.
"We are working through that now, as I say, we were only made aware of the incident late yesterday. Clearly there is an opportunity to speak to the police today. The first thing we need to do is identify who the individual is.
"We'll get outstanding co-operation from the Massey Club themselves - clearly [for] the individual to do what he has done, you would logically think he has a relationship with someone involved in that particular team."
He said the incident was not "normal behaviour".
"Certainly in our environment, I mean you have got to think there is probably 30,000 to 40,000 spectators on the sidelines each week. During the rugby season we have had close to five months of rugby, and we have only had one judicial hearing in the entire season to date."
Mr Hollister told Newstalk ZB it was fortunate these incidents happened rarely.
"It's the first time it's happened in our environment and we will be treating it very seriously. This is one isolated incident... we put a lot of effort, along with New Zealand Rugby, in around encouraging positive sideline behaviour. Let's hope it doesn't happen again."